These studies on ketogenesis in the ruminant have been directed primarily toward a better basic understanding of ketogenesis and toward improved procedures for the control of ketosis in dairy cows. Insulin levels in ketotic cows have been compared to normal cows. Significant positive within-cow correlations between serum insulin and blood glucose sggest tht blood glucose plays a major role in regulating insulin level in the ketotic cow. Although the low insulin levels at the time of ketosis may accentuate some of the metabolic changes, there was no evidence that abnormal insulin secretion was a causative factor in ketosis. Alloxan-diabetic goats showed expected low serum insulin levels and high blood glucose, ketone, FFA, triglyceride, and acetate levels. All were similar to changes in the ketotic cow except for triglycerides, which are low in ketosis. Studies have been conducted on the mechanism of action of nicotinic acid in causing recovery from ketosis. Injection of labeled palmitate in goats during the inhibition and rebound phases of lipolysis following nicotinic acid showed that ketogenesis from FFA was inhibited initially but markedly increased during the rebound.